1. Field of the Invention
The present invention relates to a photoelectric conversion device.
2. Related Background Art
It is well known that photo-sensors are used as photoelectric conversion devices in various picture information handling apparatus such as facsimiles, digital copiers and character readers. In modern apparatus, photo-sensors are arranged linearly to form a long sensor. The sensor is capable of reading picture image with a high level of accuracy. Recently, as a photosensor which provided an inexpensive high-speed picture reading apparatus, a sensor has been proposed in which a thin film transistor (referred to as TFT hereinafter) of amorphous silicon is connected to a photoelectric converting section which is constituted by an array of photo-sensor elements which also are made of amorphous silicon. The photo-sensor of this type is inexpensive and is capable of reading picture information at a high speed. In this sensor, parallel signals output from the array of photo-sensor elements are changed into a serial signal by means of the switching TFT. This arrangement enables the number of the driving ICs to be decreased, thereby reducing the cost of the driving circuit.
In the photosensor employing a TFT, however, is disadvantageous in that the number of steps is increased because the photoelectric conversion section and the TFT have to be produced independently, with the result that the production cost is increased and that the yield is lowered.